cross-posted from: https://mander.xyz/post/18022653
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yeah this thing thats become popular is so annoying because it assume some straight arrow shot into the sun when you just want to send the item into an unstable orbit. The suns gravity well is all you need to get it into.
Even without actively accelerating toward the sun, something starting on earth is already orbiting the sun at about 100,000 km/h. You’d have to cancel that out by accelerating the same amount in the opposite direction just to be able to fall into the sun’s gravity well instead of continuing to orbit. That would take quite a bit of propellant.
why would you be fighting our velocity. you just need to nudge away in the direction it can still be moving with our velocity. that is what an orbit is. again it does not need to be an arrow blasting in a straight line at the sun it just needs to have an orbit that is falling into it.
But even though the Sun has such a powerful pull, it’s surprisingly hard to actually go to the Sun: It takes 55 times more energy to go to the Sun than it does to go to Mars.
Why is it so difficult? The answer lies in the same fact that keeps Earth from plunging into the Sun: Our planet is traveling very fast — about 67,000 miles per hour — almost entirely sideways relative to the Sun. The only way to get to the Sun is to cancel that sideways motion.
Edit: replaced a bad explanation with a very good explanation: Hitting the Sun is HARD
Related, The Most Confusing Things About Spacecraft Orbits is maybe the best primer for basic orbital mechanics for people who haven’t played KSP